The basic concept and architecture of software radio is introduced in this paper. And a type of software radio receiver based on programmable digital down converter (DDC) -hsp50214b is presented.

One of the important conceptions of Software Radio is to make A/D converter close to antenna, we should convert IF analog signal even RF analog signal into digital signal.

Combining to devise radio telemetry receiver, the application of digital down converter and frequency demodulation in software radio is discussed and analysed.